There are several synonyms for the phrase "official inspector." Some common alternatives include "authorized examiner," "government inspector," and "licensed investigator." Other possibilities might include "regulated auditor," "public examiner," or "accredited check-up agent." Depending on the specific context, other related terms might be more appropriate. For example, a building inspector could also be referred to as a "code compliance officer," while a quality control inspector might be called a "product reviewer" or "testing specialist." Ultimately, the most effective synonym will depend on the industry, situation, and intended meaning.